Businesses or other entities having a need for volume printing typically purchase a production printer. A production printer is a high-speed printer used for volume printing, such as 100 pages per minute or more. The production printers are typically continuous-form printers that print on paper or some other printable medium that is stored on large rolls.
A production printer typically includes a localized print controller that controls the overall operation of the printing system, a print engine (sometimes referred to as an “imaging engine” or as a “marking engine”), and a dryer. The print engine includes one or more printhead assemblies, with each assembly including a printhead controller and a printhead (or array of printheads). An individual printhead includes multiple tiny nozzles (e.g., 360 nozzles per printhead depending on resolution) that are operable to discharge colorants as controlled by the printhead controller. The printhead array is formed from multiple printheads that are spaced in series along a particular width so that printing may occur across the width of the medium. The dryer is used to heat the medium to dry the colorant.
In dryers that apply a great deal of heat over a short period of time, it remains a problem to ensure that the medium is properly dried. Too much heat can cause the medium to char or burn. At the same time, too little heat can result in the colorant on the medium remaining wet, resulting in smearing or offsetting that reduces the print quality of jobs. Further, large variations in temperatures across the medium can arise during the heating process due to the varying densities of colorant applied to the medium and variations in the energy absorption characteristics of the colorants. This may cause problems with the medium such as curling or wrinkling due to non-uniform stresses across the medium during this high rate of thermal change. These problems are typically amplified as the paper cools in an uncontrolled and non-uniform manner.